From e84b5f824475a05ab54a9e49b8246b42bb1aa4e7 Mon Sep 17 00:00:00 2001
From: Steven Kirk <grokys@gmail.com>
Date: Wed, 22 Dec 2021 15:07:55 +0100
Subject: [PATCH] Added AvaloniaLocation.GetRequiredService.

Using the pattern from elsewhere e.g. https://docs.microsoft.com/en-us/dotnet/api/microsoft.extensions.dependencyinjection.serviceproviderserviceextensions.getrequiredservice?view=dotnet-plat-ext-6.0
---
 src/Avalonia.Base/AvaloniaLocator.cs  | 10 ++++++++++
 src/Avalonia.Controls/SystemDialog.cs |  9 +++------
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/src/Avalonia.Base/AvaloniaLocator.cs b/src/Avalonia.Base/AvaloniaLocator.cs
index 0510852ea7..8ec245507b 100644
--- a/src/Avalonia.Base/AvaloniaLocator.cs
+++ b/src/Avalonia.Base/AvaloniaLocator.cs
@@ -125,6 +125,16 @@ namespace Avalonia
         {
             return (T?) resolver.GetService(typeof (T));
         }
+
+        public static object GetRequiredService(this IAvaloniaDependencyResolver resolver, Type t)
+        {
+            return resolver.GetService(t) ?? throw new InvalidOperationException($"Unable to locate '{t}'.");
+        }
+
+        public static T GetRequiredService<T>(this IAvaloniaDependencyResolver resolver)
+        {
+            return (T?)resolver.GetService(typeof(T)) ?? throw new InvalidOperationException($"Unable to locate '{typeof(T)}'.");
+        }
     }
 }
 
diff --git a/src/Avalonia.Controls/SystemDialog.cs b/src/Avalonia.Controls/SystemDialog.cs
index 3fac10b2d1..3487f427d7 100644
--- a/src/Avalonia.Controls/SystemDialog.cs
+++ b/src/Avalonia.Controls/SystemDialog.cs
@@ -66,8 +66,7 @@ namespace Avalonia.Controls
         {
             if(parent == null)
                 throw new ArgumentNullException(nameof(parent));
-            var service = AvaloniaLocator.Current.GetService<ISystemDialogImpl>() ??
-                throw new InvalidOperationException("Unable to locate ISystemDialogImpl.");
+            var service = AvaloniaLocator.Current.GetRequiredService<ISystemDialogImpl>();
             return (await service.ShowFileDialogAsync(this, parent) ??
              Array.Empty<string>()).FirstOrDefault();
         }
@@ -95,8 +94,7 @@ namespace Avalonia.Controls
         {
             if(parent == null)
                 throw new ArgumentNullException(nameof(parent));
-            var service = AvaloniaLocator.Current.GetService<ISystemDialogImpl>() ??
-                throw new InvalidOperationException("Unable to locate ISystemDialogImpl.");
+            var service = AvaloniaLocator.Current.GetRequiredService<ISystemDialogImpl>();
             return service.ShowFileDialogAsync(this, parent);
         }
     }
@@ -125,8 +123,7 @@ namespace Avalonia.Controls
         {
             if(parent == null)
                 throw new ArgumentNullException(nameof(parent));
-            var service = AvaloniaLocator.Current.GetService<ISystemDialogImpl>() ??
-                throw new InvalidOperationException("Unable to locate ISystemDialogImpl.");
+            var service = AvaloniaLocator.Current.GetRequiredService<ISystemDialogImpl>();
             return service.ShowFolderDialogAsync(this, parent);
         }
     }